From: "David A. Black" <dblack@...>
Date: 2005-10-14T06:47:42+09:00
Subject: Re: instance from class name?

Hi --

On Fri, 14 Oct 2005, ES wrote:

> David A. Black wrote:
>> Hi --
>> 
>> On Thu, 13 Oct 2005, Alexander Lamb wrote:
>> 
>>> Hello,
>>> 
>>> I am new to this list (and language) but I didn't find my answer from the 
>>> documentation available.
>>> 
>>> I simply would like to do something like:
>>> 
>>> myObject = class.fromName("a_class_name").new
>
> Classes are stored as constants in ruby. Witness Mr. Black's solution:
>
>> my_object = Object.const_get("MyClass").new
>> 
>> or some variation of that.
>
> That works; however, if your class name looks like SomeModule::SomeClass,
> you will need to be a bit fancier because const_get only looks for constants
> in the current class or module (the top-level Object instance is the 
> default):
>
>  class_name.split('::').inject(Object) {|parent, obj| parent.const_get 
> obj}.new

Like Kernel#singleton_class, this is one of those things that gets
written again and again, ad hoc.  I wonder if it might be a candidate
for a permanent modification to const_get....


David

-- 
David A. Black
dblack@wobblini.net